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SELECT *
FROM (VALUES
('banana'),
('selin'),
('vegetable')
) words(word)
CROSS
APPLY (SELECT CASE
WHEN ln BETWEEN 4 AND 5
THEN LEFT(word, 1) + REPLICATE('*', ln-2) + RIGHT(word, 1)
WHEN ln >= 6
THEN LEFT(word, 2) + REPLICATE('*', ln-4) + RIGHT(word, 2)
ELSE word
END as result
FROM (VALUES (LEN(words.word))) x(ln)
) calc
| word | result |
|---|---|
| banana | ba**na |
| selin | s***n |
| vegetable | ve*****le |
CREATE FUNCTION dbo.fnMaskWord(@str NVARCHAR(MAX))
RETURNS TABLE
AS RETURN (
SELECT CASE
WHEN ln BETWEEN 4 AND 5
THEN LEFT(@str, 1) + REPLICATE('*', ln-2) + RIGHT(@str, 1)
WHEN ln >= 6
THEN LEFT(@str, 2) + REPLICATE('*', ln-4) + RIGHT(@str, 2)
ELSE @str
END as result
FROM (VALUES (LEN(@str))) x(ln)
)
SELECT *
FROM (VALUES
('banana'),
('selin'),
('vegetable')
) words(word)
CROSS
APPLY fnMaskWord(word)
| word | result |
|---|---|
| banana | ba**na |
| selin | s***n |
| vegetable | ve*****le |